FIG. 14 is a diagram showing a configuration of a contactless power transmission device and surrounding devices described in Japanese Unexamined Patent Publication No. 2008-87733. In FIG. 14, the contactless power transmission device 1 includes a power feeder (primary device) F which is provided on the ground and is connected to the power source board of a power source 4, and a power receiver (secondary device) G which is mounted in an electric vehicle or a train. During power feed, the power feeder F and the power receiver G are positioned to face each other, without physical contact therebetween, i.e., with an air gap (empty space) being interposed therebetween.
In such an arrangement, when an alternating current is applied to a primary coil 2 included in the power feeder F to generate magnetic flux, electromotive force is induced in a secondary coil 3 included in the power receiver G, whereby power is contactlessly transmitted from the primary coil 2 to the secondary coil 3.
The power receiver G is connected to, for example, an in-vehicle battery 5, which is charged with the power transmitted from the power feeder F to the power receiver G. An in-vehicle motor 6 is driven by the power accumulated in the in-vehicle battery 5. Note that, during the contactless power feed process, necessary information is exchanged between the power feeder F and the power receiver G by a wireless communication device 7.
FIGS. 15A and 15B are cross-sectional views of the power feeder F (the power receiver G) of FIG. 14. FIG. 15A is a cross-sectional view of the power feeder F (the power receiver G) taken along a horizontal plane. FIG. 15B is a cross-sectional view of the power feeder F (the power receiver G) taken along a vertical plane.
As shown in FIGS. 15A and 15B, the power feeder F includes the primary coil 2, a primary magnetic core 8, a back plate 10, and a cover 11. The power receiver G includes the secondary coil 3, a secondary magnetic core 9, a back plate 10, and a cover 11. The surfaces of the primary coil 2 and the primary magnetic core 8, and the surfaces of the secondary coil 3 and the secondary magnetic core 9, are covered and fixed with a molded resin 12 containing a foam material 13. Specifically, a space between the back plate 10 and the cover 11 of the power feeder F (the power receiver G) is filled with the molded resin 12, and therefore, the surfaces of the primary coil 2 (the secondary coil 3) and the primary magnetic core 8 (the secondary magnetic core 9) provided therein are covered and fixed with the molded resin 12. The molded resin 12 is formed of, for example, silicone resin. The coverage and fixation allow the primary coil 2 (the secondary coil 3) to be positioned and fixed, and their mechanical intensity can be ensured, and at the same time, their heat can be dissipated. Specifically, the passage of an excitation current through the primary coil 2 (the secondary coil 3) releases Joule heat, which is then dissipated by heat conduction through the molded resin 12, and therefore, the primary coil 2 (the secondary coil 3) is cooled.